Method for building a serpentine heat exchanger particularly a condenser for refrigerating circuits and serpentine heat exchanger according to the said method.
The invention refers to a method for building a serpentine heat exchanger, particularly a condenser for refrigerating circuits being profiled in such a way to present from a lateral side view and relative to at least one part of its length an inclination the direction of which is suddenly or progressively inverted at least once relative to a plane which is substantially parallel to the general plane of the heat exchanger, in particular relative to a plane substantially parallel to the principal direction of a flow of air in which the exchanger is located, relative to a substantially vertical or substantially horizontal plane.
Such kinds of exchangers or condensers are known and normally they show an undulated or a xe2x80x9czigzagxe2x80x9d profile. One such heat exchanger is disclosed in GB 736155 and comprises a pipe bent into a serpentine configuration consisting of a series of substantially parallel straight pipe sections, a plurality of wires attached to each side of the serpentine configuration, the wires extending along the length of the serpentine configuration and being attached to the straight pipe sections thereof, the heat exchanger being bent at two places along its length in order to provide an undulated or zigzag profile.
From the functional point of view this kind of exchanger ensures a great improvement of the thermal exchange. Such kind of exchanger make it possible to increase the surface for thermal exchange or to increase the length of the serpentine, while maintaining their overall dimensions between certain limits.
Furthermore, the particular non-flat profile of the exchanger causes turbulences in the air flow along the exchanger thus increasing the efficiency of the thermal exchange.
On the other hand however, the manufacture of the said undulated or zigzag exchangers is not as simple as for the usual plane exchangers and the production lines for building the usual plane exchangers cannot be used to build undulated or zigzag profiled exchangers without any alteration for adaptation to the new product. Thus for the production of undulated or zigzag exchangers special lines are needed so that the costs of production rise compared to the production of usual plane exchangers.
An object of the present invention is to create a method for building a heat exchanger of the kind mentioned above, with which it is possible to avoid the aforementioned disadvantage and which ensures a low cost production of undulated and/or zigzag profiled exchangers of better quality.
The present invention achieves the before mentioned aim with a method for building exchangers of the kind mentioned at the beginning, which method is characterised by the steps of bending a pipe into a flat serpentine configuration consisting of a series of substantially parallel straight pipe sections, attaching a plurality of wires to each side of the flat serpentine configuration, said wires extending along the length of the flat serpentine configuration and being attached to said straight pipe sections thereof, and bending the flat serpentine configuration and the wires attached to it about an axis or axes corresponding to one or more of said straight pipe sections.
The bending may be made in several ways, using bending machines or utensils, dies, or other deforming tools.
In carrying out the invention it may be arranged that said flat serpentine configuration and the wires attached to it are bent about axes corresponding to alternate ones of said straight sections, and it is preferably arranged that the wires attached to opposite sides of the flat serpentine configuration are staggered one with respect to the other.
By arranging that the flat serpentine configuration is bent about an axis or axes corresponding to one or more of the straight pipe sections means that the pipe is subjected only to a torsion substantially around its own axis, and not to a bending along a transversal axis which normally leads to a weakening of the serpentine and to the reduction of the cross section of the pipe due to throttling of the pipe at the bending points.
The particularly choice of the position of the lines of bending and the staggered wires allows the bending of the exchanger from the flat configuration into the one showing at least some inclined sections avoiding any risk of tearing away the wires from the serpentine, i.e. breaking the point of soldering.
The above mentioned advantages are particularly relevant in the case of a zigzag profiled exchanger, in which there are different bending lines.
The invention refers also to a heat exchanger of the kind mentioned which comprises a pipe bent into a serpentine configuration consisting of a series of substantially parallel straight pipe sections, a plurality of wires attached to each side of the serpentine configuration, said wires extending along the length of the serpentine configuration and being attached to said straight pipe sections thereof, and characterised in that the serpentine configuration and the wires attached to it are bent about an axis or axes corresponding to one or more of said straight pipe sections.
Conveniently, it may be arranged that the serpentine configuration and the wires attached to it are bent about axes corresponding to alternate ones of said straight pipe sections, or alternatively it may be arranged that said serpentine configuration and the wires attached to it are bent about axes corresponding to different ones of said straight pipe sections to afford a zigzag profile, a saw tooth profile or an irregular profile.
Preferably, the wires attached to opposite sides of the serpentine configuration are staggered one with respect to the other.